This invention relates to an electrolyte for an electrolytic capacitor, and more particularly to an electrolyte system including 3-methoxypropionitrile as a solvent.
Electrolytes for electrolytic capacitors should be usable through a wide range of temperatures so as to provide satisfactory performance in either high or low temperature capacitor applications. It is desirable to use an electrolyte system that will form and maintain a dielectric oxide film on aluminum or tantalum foil to at least several hundred volts. Suitable electrolyte solvents must have a reasonably high dielectric constant, low viscosity, and be inert to chemical reaction. These requirements establish the solvent of the solvent of the electrolyte system as being an important factor in attaining desirable capacitor results.
Dimethylformamide (DMF) has for years been a proven solvent in electrolyte systems for electrolytic capacitors. However, the need continues for improved electrolyte systems having greater operating ranges and particularly good low temperature behavior.
It is an object of this invention to provide an electrolyte system having a maximum formation voltage for a dielectric oxide in the 300 to 500 V range together with a room temperature resistivity of substantially less than 1000 ohm-cm.